As a transparent organic polymer substrate used for optical applications, for example, as a transparent organic polymer substrate used for liquid crystal displays (LCD), touch panels, etc., a cellulose-based film such as triacetyl cellulose (TAC)-based film, a polyester-based film such as polyethylene terephthalate (PET)-based film, and the like are known.
Such a transparent organic polymer substrate lacks lubricity for handling and suffers bad handleability, and therefore a method of forming a lubricating layer on the surface to enhance the lubricity has been proposed. For producing the lubricating layer, it is known to use a binder containing inorganic particles such as silica, calcium carbonate and kaolin and/or organic particles such as crosslinked polyester.
However, in the case of using a lubricating layer formed of such a binder containing inorganic particles and/or organic particles, light is scattered by the particles contained in the binder, and thereby a problem of impairing the transparency or haze characteristics of the obtained transparent organic polymer substrate occurs.
In order to solve this problem, for example, in Patent Document 1, an optical laminate comprising a polyester film is obtained, the film having a lubricating layer which contains inorganic particles and/or organic particles, and fine particles attributable to a catalyst and satisfying specific conditions existing in the film.